Author Topic: TE0712 and PGOOD  (Read 1685 times)

DG

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TE0712 and PGOOD
« on: January 08, 2019, 04:39:42 PM »
Dear John,

I found a strange behaviour with the TE0712 (used with a custom carrier), of which I hope you are able to explain.


First:
The RESIN-pin: does this pin have internal pull-ups or pull-downs?

Second:
What are the conditions for PGOOD to get high? Is it somehow logically connected with DONE?
In my setup, I switch on the supplies for the TE0712 (VIN=3V3, 3.3VIN=3V3). Hence, the red and the green LEDs are blinking because RESIN is inactive (high) but the DONE is missing because the FPGA is not configured. The PGOOD pin remains low, although the CPLD seems to work with the supplies. Why?
If I measure the supply pins which are connected with the internally generated supplies (1V5, 1V8, 3V3), all supplies seem to be there.

After configuring the FPGA with a test software, PGOOD turns active and both LEDs are ON.

Please help me to understand this behaviour!

Kind regards,
Dino



DG

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Re: TE0712 and PGOOD
« Reply #1 on: January 09, 2019, 08:54:24 AM »
Hi again,

I have to correct my last post:
After configuring the FPGA with a test software, PGOOD stays inactive!

So again the question:
why is PGOOD false while 3.3V is already present at JM2 pins 10 and 12.

Is the meaning of PGOOD that 3.3VIN is present at the TE0712 or that all internal supplies (1.0V, 1.5V, 1.8V and 3.3V) are ready?

Kind regards,
Dino

JH

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Re: TE0712 and PGOOD
« Reply #2 on: January 09, 2019, 01:13:47 PM »
Hi,
sorry for the delay.
Question1 of your post.
RESET-IN has internal week pullup enabled on CPLD firmware. But external is recommended.

Question2:
PGOOD condition:
PGOOD is zero, if EN1 or PG_SENSE is zero else high impedance state.
PG_SENSE is 3.3V CPLD Pin 25 internal 3.3V from the module.
See schematics:
So green and red LED blinks.

Do you have external pullup on PGOOD? If not, I think this is the problem. PGOOD is no pullup on the module and is high impedance if everything is OK.

br
John

DG

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Re: TE0712 and PGOOD
« Reply #3 on: January 10, 2019, 11:12:54 AM »
Hi John,

you are right. Your link:
https://wiki.trenz-electronic.de/display/PD/4+x+5+SoM+Integration+Guide#id-4x5SoMIntegrationGuide-4x5ModuleControllerIOs
finally explains, that PGOOD is high impedance.

Unfortunately, this is not mentioned in the user guide of the TE0712. Here it is defined as an output.


Concerning the LEDs:
refering to your doc https://wiki.trenz-electronic.de/display/PD/TE0712+CPLD#TE0712CPLD-LED
they are ON, when RESIN is low (which means: the board is not running because of reset). The setup shows that they are also both ON, when RESIN = 1 and DONE = 1 (which means: everything is fine).
How can we distinguish those cases then?

Kind regards,
Dino

JH

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Re: TE0712 and PGOOD
« Reply #4 on: January 10, 2019, 12:06:37 PM »
Hi,

Quote
Unfortunately, this is not mentioned in the user guide of the TE0712. Here it is defined as an output.
sorry for this not correct written TRM. I will change this.
If you has still problems with this signal, please write to "support@trenz-electronic.de" I can create a custom firmware, where PGOOD is defined as output.

To your LED question:
LED has double usage.
  • If system hold into reset, both will be on.
  • If system is not hold into reset and FPGA is not programmed, LEDs will be blinking.
  • If system is not hold into reset and the FPGA is programmed, both LEDs are controlled by the design on the module. Red LED from FPGA U22 PIN and Green from FPGA W22 PIN. But in this case the FPGA must be programmed and you see this on Vivado for example.
A general firmware update is planned with internal pullup for pgood and new LED sequencing, but I can't tell a timeline for this task at the moment.

br
John

DG

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Re: TE0712 and PGOOD
« Reply #5 on: January 10, 2019, 01:27:42 PM »
Okay John,

thank you very much for this additional information!!!

Kind regards,
Dino

tschesnok

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Re: TE0712 and PGOOD
« Reply #6 on: March 20, 2021, 05:11:02 PM »
Hi,
sorry for this not correct written TRM. I will change this.
If you has still problems with this signal, please write to "support@trenz-electronic.de" I can create a custom firmware, where PGOOD is defined as output.

To your LED question:
LED has double usage.
  • If system hold into reset, both will be on.
  • If system is not hold into reset and FPGA is not programmed, LEDs will be blinking.
  • If system is not hold into reset and the FPGA is programmed, both LEDs are controlled by the design on the module. Red LED from FPGA U22 PIN and Green from FPGA W22 PIN. But in this case the FPGA must be programmed and you see this on Vivado for example.
A general firmware update is planned with internal pullup for pgood and new LED sequencing, but I can't tell a timeline for this task at the moment.

br
John

Looks like I just spun a board assuming PGOOD is an output! This has NOT been corrected in the 712 PDF Manual I'm using as of March 2021. Mistakes happen.. but to see this happen to me when it has long been discovered.. ugh..
I will email support as suggested.
 

JH

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Re: TE0712 and PGOOD
« Reply #7 on: March 22, 2021, 09:50:23 AM »
Hi, thank you for pointing out this.
I'm sorry for confusion.

Unfortunately, control signals were not solved uniformly on the different 4x5 modules.  Not all 4x5 modules use all control signals and also pullups/downs are not always implemented on the module. for most compatibility on your own carrier(in case you want to add different 4x5 modules series)  I would recommend to check also this
https://wiki.trenz-electronic.de/display/PD/4+x+5+SoM+Integration+Guide#id-4x5SoMIntegrationGuide-4x5ModuleControllerIOs

br
John